Sudden drastic Calcium spike?

[Xefan]

Hi,

I'm still fairly new to the hobby, I've only been running my tank a few months. We installed a Trident about a week ago and it showed our Calcium was too high, way up at about 576. I think we'd been misreading our Red Sea test kits and over-dosing as a result. Since then Calcium has slowly been coming down, reaching 503 at midnight last night, so I was happy with that.

At lunchtime today the second daily test ran, and showed Calcium had skyrocketed in 12 hours from 503 to 613. I thought this might be a bad test, so I made the Trident re-run it and it then said 637.

We've not added anything in this timeframe, and the only things going on in the tank are that a small rock with some zoas on slipped from it's perch last night (our conch was under it when I lifted it off), and our pistol shrimp has been super active digging away this morning since first thing, we don't usually see him until later on which is a bit unusual, but he looks healthy as does his goby friend.

Our Alkalinity has been sliding up and has reached 11.25. Other measurements (either from Trident, or taken by Hanna tests) are:
Magnesium: 1405
Phosphate: 0.03
Ammonia: 0.006
Salinity: 33.9
Nitrate: 8.5
PH: 8.14

The only thing I can think could've caused this is the rock falling off with the Zoa on; I moved it down to the sand to prevent it falling again, but where it was is covered in white chalky substance like as though you rubbed a bit of chalk against a rock. Could the rock this Zoa was on have been insanely Calcium rich and whatever knocked it off caused it to leech out?

This is in a 300 litre tank. It looks fairly happy and healthy otherwise.

 

[KrisReef]

How are you adjusting Calcium/alk?
Something seems to be adding calcium, otherwise you have a testing error?

 

[jda]

It is possible that calcium is that high if you dosed it and nothing has used any. Salt mixes are not that high, so if you never dosed any calcium then the test kit is likely bad.

Those seem like testing errors to me. No way to swing 100ppm overnight without any additions.

Segal's law is all too real with reefing. You need to pick something and have that be your standard. For me, it is Salifert test kits for alk and calcium. Maybe that is Red Sea test kit for you. Whatever it is, you need to just pick and put your faith into something that you control - not ICP or stuff like that.

My guess is that your calcium is about 500 with the alk at 11ish. The trident is not testing things right. I am not a very good guesser, though.

 

[Randy Holmes-Farley]

The spike is test error.

 

[Xefan]

So I have a pair of DOS for dosing but they're not even out the boxes yet much less setup, so the spike can't be down to adding anything because nothing has been added other than the usual fish food.

It sounds like it's probably a test error then from what people are saying. I've set the Trident to calibrate and will see what it comes up with after that. The Red Sea test kit just gave us about 470 for calcium so it does sound like the Trident has gone off the rails in it's calcium measurement for some reason.

 

[jda]

I know that Neptune says otherwise, but Trident is not always a precision instrument. People who waited for months or a year to get one were selling them not long afterwards. There are some Trident threads that you can find that might be able to help.

I would trust that Red Sea test kit.

 

[Xefan]

Post calibration the Trident is giving me the following:

Alkaline: 10.06
Calcium: 554
Magnesium: 1288

These figures sound much more plausible, though still a fair way off from the Red Sea test. I'll monitor it and see what it does for a few days.

 

[Randy Holmes-Farley]

FWIW, all of the values are OK, so I understand the concern, but there's no immediate action needed.